Clay materials are often present in construction materials such as concrete, mortar, asphalt, road base, and gas and oil well drilling mud (used for cementing the annulus gap between pipe and well bore) due to their presence in sand, crushed rock or gravel, and other aggregate materials which are typically used in construction applications. Having a lamellar structure, clay can absorb water and chemical agents, resulting in decreased performance of the construction materials. A common method to mitigate the deleterious effect of clays is to wash them from the aggregates. However, beneficial fines can also be removed during washing.
It is known to use quaternary amine compounds for modifying properties or characteristics of clays. For example, in U.S. Pat. Nos. 6,352,952 and 6,670,415 (owned by W. R. Grace & Co.-Conn.), Jardine et al. disclosed that quaternary amines could be used to minimize the adverse effect of clays on dosage efficiency of superplasticizers used in concretes manufactured using sand aggregates that contained such clays.
As another example, in U.S. patent application Ser. No. 11/575,612 (Publ. No. 2007/0287794 A1) and U.S. patent application Ser. No. 11/575,607 (Publ. No. 2008/0060556 A1), assigned to Lafarge S. A., Jacquet et al. disclosed compositions for “inerting” clays in aggregates which included quaternary amine functional groups, such as diallyldialkyl ammonium, quaternized (meth)acrylates of dialkylaminoalkyl and (meth)acrylamides N-substituted by a quaternized dialkylaminoalkyl. Included among these groups were cationic polymers obtained by polycondensation of dimethylamine and epichlorohydrin. Similar compositions were disclosed by Brocas in World Intellectual Property Organization Application (Publ. No. 2010/112784 A1), also assigned to Lafarge S. A.
This invention is related to a method and composition using a functionalized polyamine for mitigating detrimental effects of clays while leaving beneficial fines. One objective of the present invention, therefore, is to mitigate the deleterious effects of clays while improving properties of the construction materials. Advantages of this invention include the improvement of mortar and concrete properties (e.g., workability, strength), asphalt properties (e.g., binder demand), and road base properties (e.g., improved flowability). As a result, washing can be reduced or eliminated, and this allows for a greater content of beneficial fines (i.e., small aggregates) to remain in the construction material.
Additional benefits can also be realized for clay stabilization in gas and oil well applications (involving fractured rock formations) to reduce water loss.